1. Technical Field
The present invention relates to an electronic appliance, and more particularly to a display device for displaying images in an electronic appliance.
2. Description of the Related Art
In general, a portable appliance is a category of an electronic appliance and refers to an appliance that can be carried by a user during its operation of receiving and displaying/reproducing various contents. Examples include portable terminals, MP3 players, PMPs (Portable Multimedia Players), electronic books, etc.
Due to the easy portability of portable electronic appliances and various functions installed therein, portable terminals are frequently used while the users thereof are in motion. The physical styles (form factors) of portable electronic appliances have evolved in accordance with the applications, periodic trend changes and consumer demand. Rectangular shaped (bar-type) portable terminals having expanded functionality, such as smart phones and tablet PCs, have become increasingly popular.
In particular, as electronic scheduler and multimedia functions are incorporated in the bar type portable terminals, it becomes possible to display various contents and perform widespread functions, from voice calling to banking transactions, game/multimedia service and wireless Internet service, etc. with a single portable terminal. In such a bar-type portable terminal, data input devices for inputting data, selecting icons, etc. and data output devices for outputting images and data are implemented through one large display device on the front side thereof.
A display device for today's electronic appliances includes a touch screen panel and an LCD (Liquid Crystal Display) panel provided on the rear side of the touch screen panel. Recently, the sizes of bar-type electronic appliances have progressively increased to realize the largest screen possible as long as they are portable.
A conventional display device for an electronic appliance is disclosed in Korean patent publication No. 10-2011-0047531 published on Aug. 9, 2011 and entitled “Touch Screen Panel.”
FIGS. 1, 2 and 3 show an exploded perspective view broadly illustrating a conventional display device for an electronic appliance, a top plan view of the display device in the assembled state, and cross-sectional views taken along lines A-A′ and B-B′ of FIG. 2, respectively.
Referring to FIGS. 1 to 3, a display device 1 for an electronic appliance includes a touch screen panel 2, an LCD panel 3 provided behind the touch screen panel 2, and a “sponge” 4 provided between the touch screen panel 2 and the LCD panel 3. Sponge 4 has the shape of a rectangular frame. The touch screen panel 2 has a larger area than the LCD panel 3, and the sponge 4 is sized and positioned such that the outer periphery of the LCD panel 3 overlays a central region of the sponge's frame (as indicated by the dotted lines in FIG. 1).
The sponge 4 interposed between the touch screen panel 2 and the LCD panel 3 is provide to form a space S between the touch screen panel 2 and the LCD panel 3. In addition, the sponge 4 maintains the space S between the touch screen panel 2 and the LCD panel 3 in a sealed state.
An inner periphery 4b of the sponge 4 is smaller than the outer periphery 3a of the LCD panel. Therefore, the outer periphery 4a of the sponge 4 is laid between the outer periphery 3a of the LCD panel 3 and the outer periphery 2a of the touch screen panel 2, and the inner periphery 4b of the sponge 4 is laid inside of the outer periphery 3a of the LCD panel 3.
The sponge 4 prevents foreign matter, such as dust, from being introduced into the space S between the LCD panel 3 and the touch screen panel 2, and dampens impact applied to the LCD panel 3 by the touch screen panel 2 as the touch screen panel 2 is pushed. In addition, when the touch screen panel 2 is pushed via touch contact, the air confined by the sponge 4, the touch screen panel 2 and the LCD panel 3 applies a force to the touch screen panel 2 to return the touch screen panel 2 to its original position.
One or more grooves 5 are formed on one side of the inner periphery 4b of the sponge 4 and extend outwardly from the inner periphery 4b of the sponge 4. In a state in which the touch screen panel 2, the sponge 4 and the LCD panel 3 are assembled in this order, the grooves 5a extend outwardly beyond the outer periphery of the LCD panel 3. Thus the space S between the touch screen panel 2 and the LCD panel 3 is “connected” to the exterior through gaps formed at the end parts of the grooves 5 (hereinafter, the gaps will be referred to as an “air communication holes 5a”) (see, the cross-sectional view taken along line B-B′ in FIG. 3).
Therefore, the air confined in the space S between the touch screen panel 2 and the LCD panel 2 is caused to flow out to the outside through the air communication holes 5a via the pressure applied in touching the touch screen panel 2. The air is caused to flow into the space S through the air communication holes 5a when the touch pressure is removed.
With each of the air communication holes 5a formed by a portion of a groove 5 that is not covered by the LCD cover 3, the air communication holes 5a are very narrow. Therefore, after flowing out to the outside through the air communication holes 5a and through the junction surfaces of the sponge 4 (between the touch screen panel 2 and the sponge 4 or between the LCD panel 3 and the sponge 4) from the space S, air flow back into the space through the air communication holes 5a is restricted and is slow to return. Such restriction is due to a pressure differential between the inside and outside air occurring as a consequence of the touch pressure. As a result, there is a problem in that the touch screen panel 2 and the LCD panel 3 become more closely spaced with one another.
As the touch screen panel 2 and the LCD panel 3 become more closely spaced with each other, an oil film phenomenon occurs, by which rainbow colors appear through the touch screen panel 2.
If the air can be reintroduced between the touch screen panel 2 and the LCD panel 3, the pushed touch screen panel can be rapidly returned to its original position due to the increase of the spatial volume due to the introduction of the air. As a result, even if the oil film phenomenon occurs, the oil film can be rapidly removed. However, since the reintroduction of air through the air communication holes 5a is restricted, the removal of oil film phenomenon may be very slow or may not be executed.
In particular, if the sponge 4 is not arranged at its correct position between the touch screen panel 2 and the LCD panel 3, the grooves 5 may be entirely covered by the LCD panel 3 to such an extent that the air communication holes 5a are not formed. In this condition, the space S between the touch screen panel 2 and the LCD panel 2 is not connected to the outside. If, however, the air between the touch screen panel 2 and the LCD panel 3 escapes to the outside through the sponge 4 as the touch screen panel 2 is pushed, a problem arises in that air may be unable to flow back into the space S.